Air starter



April 16, 1968 G. VAN NEDERYNEN ETAL 3,377,921

AIR STARTER 2 Sheets-Sheet 1 Filed Aug. 4, 1966 INVENTORS 6341?) WIN NEDERY/VEN HUG/+8. TAYLOR BY v \JTXM ATTORNEY April 1968 G. VAN .NEDERYNEN ETAL 3,377,921

AIR STARTER Filed Aug. 4, 1966 2 Sheets-Sheet 2 NVENTORS FIG- 3 mm mm wmmr/vs/v HUGH g TAYLOR m w Tm ..ATTOR NEX.

United States Patent 3,377,921 AIR STARTER Gerrit Van Nederynen, Sayre, Pa., and Hugh B. Taylor, Waverly, N.Y., assignors to Ingersoll-Rand Company, New York, N. a corporation of New Jersey Filed Aug. 4, 1966, Ser. No. 570,328 7 Claims. (Cl. 91-53) This invention relates to pneumatically operated air starters for internal combustion engines and, more particularly, to the type of starter known as a positive-engagement air starter. An example of a positive-engagemen air starter is disclosed in the United States Patent No. 3,051,136, issued to R. J. Muehlhausen on Aug. 28, 1962.

The starter disclosed in the Muehlhausen patent has the undesirable characteristic of occasionally failing to operate, when the starter control is actuated. This occasional failure is caused by the pinion abutting and stopping against the end face of an engine ring gear. The pinion drive mechanism includes a spiral spline which is intended to prevent end face abutment between the pinion and ring gear by rotating the pinion slightly as its air piston moves relative to the pinion. However, experience has proved that, instead of the pinion rotating, the splines act to rotate the air motor in a reverse direction while the pinion remains stationary. If the pinion remains in end face abutment with the ring gear, the piston fails to uncover the port leading to the pilot-operated valve controlling the feeding of compressed air to the starter motor, and, as a result, the main starter valve remains closed, and the starter motor fails to operate.

The principal object of this invention is to provide an air starter of the positive-engagement type which substantially eliminates or minimizes the disadvantages inherent in prior art air starters of this type.

Other important objects of this invention include: to provide an air starter of the positive-engagement type which operates even when the pinion is in end face abutment with the engine ring gear; to provide an air starter of this type having a pilot-operated main valve which opens in response to a predetermined high pressure; and to provide an air starter of this type which normally delays the feeding of compressed air to the starter motor until after the pinion is moved axially into either meshing or end face abutment with the engine ring gear.

The invention is disclosed in the accompanying drawings wherein:

FIG. 1 is a longitudinal section of the air starter and showing the air starting system of this invention connected to the air starter;

FIG. 2 is an enlarged fragmentary sectional view of the air starter of FIG. 1 and showing the pinion engagement means of the starter;

FIG. 3 is a section taken on line 3-3 of FIG. 2; and

FIG. 4 is a section taken on line 4-4 of FIG. 2.

The air starter 1 shown in FIG. 1 includes a casing jointly comprising a motor housing 2, a gear reduction housing 3 fixed to the front of the motor housing 2 and a pinion housing 4 fixed to the front of the gear reduction housing 3-, resulting in the gear reduction housing 3 being interposed between the motor housing 2 and the pinion housing 4. The pinion housing 4 is adapted to be bolted to the flywheel housing of an engine (not shown) for mounting and supporting the starter 1 on the engine. The motor housing 2 contains an air motor rotor 6 driving a reduction gear train 7 contained in the gear reduction housing 3. The reduction gear train 7 drives a shaft 9 which projects into the pinion housing 4 and is connected to a pinion 10. The pinion 10 is adapted to engage the ring gear 11 of amengine flywheel during the Patented Apr. 16, 1968 starting of the engine. All of the foregoing structure is conventional.

Pinion engagement means ,9 between a position wherein the pinion 10 is disengaged from the ring gear 11, as shown in FIG. 1, and a position wherein the pinion 10 is engaged with the ring gear 11, as shown in FIG. 2. The pinion shaft 12 is moved axially on the shaft 9 by a pinion engagement means.

The pinion engagement means includes a cylinder 14 formed in the pinion housing 4 coaxially with the shaft 9. A piston 15 is slidably mounted in the cylinder 14 with the outer circumference of the piston 15 sliding on the walls of the cylinder 14. The gear reduction housing 3 includes a radial shoulder 16 carrying an annular flange 21 which projects forward into the cylinder 14 and slidably engages the inner periphery of the piston 15. The piston 15 carries inner and outer -O-rings 22 and 23 seating against the walls of the cylinder 14 and the flange 21, respectively. The actuating chamber 24 of the piston 15 is bordered by the piston shoulder 16, the cylinder walls 14 and the head flange 21, with the O-riugs 22 and 23 acting to seal the clearance between the piston 15 and the adjacent surfaces.

Compressed air is admitted to the chamber 24 through an inlet port 25 formed in the casing of the starter rearwardly of the piston 15 and opening into a longitudinal passage 26 which in turn, extends into the actuating chamber 24. As shown in FIG. 4, the forward end of the passage 26 is formed by a radial notch 26' provided in the rear face of the pinion housing 4. The admission of compressed air through the inlet port 25 and the passage 26 to the actuating chamber 24 causes the piston 15 to be moved forward in the cylinder 14 to its forward position, as shown in FIG. 2. The piston 15 is normally biased rearwardly in the cylinder 14 by a light compression spring 27 disposed between the piston 15 and the front end of the cylinder 14.

The pinion shaft 12 is rotatably movable in the piston 15. The means for rotatably mounting the piston 15 to the pinion shaft 12 includes an enlarged cylindrical drum 28 fixed on the rear end of the pinion shaft 12 and rotatably seated in an annular groove 29 formed in the interior of the piston 15. The drum 28 is locked in the groove 29 by a lock ring 30 fitting in a suitable internal undercut formed in the groove 29. Suflicient clearance is provided between the piston 15, drum 28 and the lock ring 30 to allow the drum 28 to rotate freely in the piston 15 while locking the piston 15 and drum 28 together for axial movement.

The main drive shaft 9 is connected to the drive shaft 12 by an overrunning or unidirectional clutch 31 allowing the pinion shaft 12 to be driven by the shaft 9 in one direction and to free wheel in the other direction. The overrunning clutch 31, is formed by a series of circumferentially spaced tilting wedges 32 located between an inner race 33 splined on the shaft 9 and an outer cylindrical surface 34 formed on the interior of the drum 28. The wedges 32 are disposed axially between a pair of roller bearings 36 which allow the drum 28 to rotate freely on the inner race 33 when the clutch 31 is released. The splines 37 provided on the main drive shaft 9 allow the clutch 31 to slide axially on the shaft 9 while the inner race 33 remains keyed to the shaft 9. The clutch 31 allows the pinion 10 to overrun the starter motor 6 when the engine starts and the pinion 10 is still meshed with the ring gear 11. The specific details of the overrunning clutch 31 are not important since various types of overrunning clutches can be used with this starter.

Compressed air circuit Looking at FIG. .1, compressed air is fed from a suitable source (not shown) to a T fitting 45 mounted on the inlet side of a pilot valve or diaphragm controlled valve 46. The diaphragm valve 46 has its outlet side connected by a nipple 47 to the inlet port 48 of the rotary air motor housing 2. In addition to its function as a pipe, the nipple 47 serves to support the diaphragm valve 46 on the starter frame 1.

The stem of the T fitting 45 is interconnected by a suitable hose 50 to the inlet of a starter valve 51, which is normally mounted adjacent the dashboard of a vehicle when the starter is used in a motor vehicle such as a truck. The outlet of the starter valve 51 is connected by a hose 52 to the inlet port 25 of the pinion engagement cylinder 14.

The starter valve 51 may be of any suitable type which, when in a closed position, will exhaust the hose 52 to atmosphere and, when open, will admit compressed air from the hose 50 to the hose 52. The valve 51 shown in FIG. 1 is of the pull-knob type and includes a body, also designated 51, an axially movable valve rod 53 having a knob 54 at its outer end and a valve plug 55 at its inner end seating in a conical valve seat formed in the valve body 51. A spring surrounds the rod 53 and normally biases the valve plug 55 against its seat to close the valve. When the valve 51 is closed, the hose 52 is vented to atmosphere through a vent port 56 in the valve body 51.

Opening the starter valve 51 admits compressed air to the hose 52 and through the port 25 into the actuating chamber 24 of the pinion engagement cylinder 14. As previously explained, the compressed air forces the piston 15 forward and moves the pinion into engagement with the flywheel ring gear 11. After the piston stops at the forward end of its movement, the pressure in the actuating chamber 24 rises until it opens the diaphragm valve 46. Pressure in the chamber 24 is transmitted through an outlet port 58 and a hose 59 to the diaphragm chamber 60 of the diaphragm valve 46. The outlet port 58 is connected to the actuating chamber 24 by a passage 66 formed in the starter housing and including a radial notch 67 formed in the rear face of the pinion housing 4, shown in FIG. 4. I

The diaphragm valve 46 is conventional and includes the diaphragm chamber 60 which contains a flexible diaphragm 61 connected to a valve element 62 seating in a valve seat 63. A spring 64 biases the valve element 62 against the seat 63 to normally close the diaphragm valve 46 and prevent the compressed air fed from the T fitting 45 from entering the nipple 47 and the rotary motor of the starter. The diaphragm valve 46 is selected to begin opening under a higher air pressure than the air pressure needed to urge the piston 15 to its forward position in the pinion housing 4. After the piston 15 in the pinion housing 4 moves forward and the pressure in the actuating chamber rises sufficiently, the compressed air flows through the outlet port 58 and the hose 59 into the diaphragm chamber 60 and acts on the diaphragm 61 to open the valve element 62, thus allowing compressed air to flow through the valve 46 to the rotary motor of the starter.

Operation When the starter 1 is at rest, both of the air hoses 52 and 59 are vented to atmosphere, the piston 15 is retracted so that the pinion 10 is disengaged from the ring gear 11, the starter valve 51 and diaphragm valve 46 are closed and the rotary motor 6 is stationary. When it is desired tcuse the starter, the operator simply opens the starter valve 51 and the remainder of the operation 4 of the starter proceeds without the operator doing anything fulther.

The opening of the starter valve 51 feeds compressed air through the hose 52 and inlet port 25 into the actuating chamber 24 of the pinion housing causing the piston 15 to be forced forward under a relatively low air pressure. In an example starter, the piston will begin moving forward under 5 psi. in the actuating chamber 24. The piston 15 carries the pinion 10 into engagement with the ring gear 11 so that the starter is now ready for its rotary motor to start. Compressed air in the chamber 24 continues to rise to a higher pressure and is fed through the hose 59 to the diaphragm valve 46. When the pressure in the chamber 24 rises sufiiciently to a relatively higher air pressure, the diaphragm valve 46 will open and admit compressed air to the rotary motor 6. In an example starter, the valve 46 will begin opening under 20 p.s.i. and will be fully open at 40 psi. This compressed air actuates the rotary motor 6 which drives the pinion 10 through the reduction gear train '7.

Although the preferred embodiment uses a diaphragm valve 46 which is selected to begin opening under a higher air pressure than the air pressure required to move the piston 15 to its forward position, there are other Ways of insuring that the valve 46 does not open before the piston 15 is moved forward. For example, the passage 66, outlet port 58 or hose 59 can contain a restriction that is sufficiently small in area to delay the rise in air pressure in the diaphragm chamber 6% until the piston 15 is moved forward to engage the engine ring gear 11,

While a preferred embodiment of the invention has been illustrated and specifically described in detail, it should be recognized that the invention can be changed in various ways and aspects without changing the novel concepts of the invention and, therefore, this invention is not considered to be limited to the described embodiment.

Having described our invention, we claim:

1. An air-operated starter adapted to engage and rotate the flywheel ring gear of an engine, comprising:

a frame adapted to be fixed to the engine adjacent the flywheel ring gear;

a compressed air-operated rotary motor contained within said frame;

a drive train driven by said motor and including a pinion mounted within said frame for axial movement between a pair of positions, including a normally disengaged position with said ring gear and an engaged position with said ring gear;

means biasing said pinion to its normal disengaged position;

air-operated pinion engagement means contained within said frame and operative, when supplied with compressed air, to move said pinion to its engaged position;

first valve means for supplying compressed air to said air-operated pinion engagement means to cause it to engage said pinion with the flywheel ring gear; and

second valve means operative, in response to an increased air pressure in said air-operated pinion engagement means occurring at the end of the move ment of said pinion toward said engaged position, after the opening of said first valve means, to admit compressed air to said rotary motor for driving said pinion and the flywheel ring gear.

2. The starter of claim 1 wherein said air-operated pinion engagement means includes:

a cylinder contained in said frame and axially aligned with said pinion; and

a piston reciprocating in said cylinder and connected to said pinion to reciprocate it axially between its dis engaged and engaged positions.

3. The starter of claim 2 wherein:

said first valve means includes a first port in said cylinder for admitting compressed air behind said piston;

said second valve means includes a second port in said cylinder spaced from said first port and open to said first port at all times; and

said second port is connected to a means responsive, when a predetermined pressure is admitted to said second port, to admit compressed air to said rotary motor.

4. The starter of claim 3 including:

a pilot-operated valve connected to said second port and operative, when receiving said predetermined pressure from said second port, to admit compressed air to said rotary motor to drive said pinion.

5. The starter of claim 4 wherein:

said pinion is connected to said rotary motor by an overrunning clutch which allows the pinion to override the rotory motor.

6. An air-operated starting system for an engine having a flywheel ring gear, comprising:

a starter including an air-operated rotary motor and a drive train for connecting said motor to the flywheel flywheel ring gear, means biasing said pinion to its disengaged position, and air-operated pinion engagement means for moving said pinion to its engaged position;

a compressed air source;

first valve means connected to said source and operative, when actuated, to supply compressed air to said air-operated pinion engagement means; and

second valve means operative, in response to an increase in air pressure to a predetermined air pressure in said cylinder after said pinion is moved to its engaged position, to supply compressed air to said rotary motor.

7. The starting system of claim 6 wherein:

said second valve means includes a pilot-operated valve' connected to said compressed air source and said rotary motor and operative to open, in response to the application of a predetermined air pressure.

No references cited.

EDGAR W. GEOGHEGAN, Primary Examiner. 

1. AN AIR-OPERATED STARTER ADAPTED TO ENGAGE AND ROTATE THE FLYWHEEL RING GEAR OF AN ENGINE, COMPRISING: A FRAME ADAPTED TO BE FIXED TO THE ENGINE ADJACENT THE FLYWHEEL RING GEAR; A COMPRESSED AIR-OPERATED ROTARY MOTOR CONTAINED WITHIN SAID FRAME; A DRIVE TRAIN DRIVEN BY SAID MOTOR AND INCLUDING A PINION MOUNTED WITHIN SAID FRAME FOR AXIAL MOVEMENT BETWEEN A PAIR OF POSITIONS, INCLUDING A NORMALLY DISENGAGED POSITION WITH SAID RING GEAR AND AN ENGAGED POSITION WITH SAID RING GEAR; MEANS BIASING SAID PINION TO ITS NORMAL DISENGAGED POSITION; AIR-OPERATED PINION ENGAGEMENT MEANS CONTAINED WITHIN SAID FRAME AND OPERATIVE, WHEN SUPPLIED WITH COMPRESSED AIR, TO MOVE SAID PINION TO ITS ENGAGED POSITION; FIRST VALVE MEANS FOR SUPPLYING COMPRESSED AIR TO SAID AIR-OPERATED PINION ENGAGEMENT MEANS TO CAUSE IT TO ENGAGE SAID PINION WITH THE FLYWHEEL RING GEAR; AND SECOND VALVE MEANS OPERATIVE, IN RESPONSE TO AN INCREASED AIR PRESSURE IN SAID AIR-OPERATED PINION EN- 